a. Field of the Invention
The instant invention relates to a catheter assembly with a front-loaded catheter tip and having a multi-contact connector. In particular, the instant invention relates to catheters comprising multi-contact connectors at the proximal end that allow for electrical connections in constrained spaces.
b. Background Art
It is known that catheters are widely used to perform a variety of functions relating to therapeutic and diagnostic medical procedures involving tissues within a body. For example, catheters can be inserted within a vessel located near the surface of a body (e.g., in an artery or vein in the leg, neck, or arm) and maneuvered to a region of interest within the body to enable diagnosis and/or treatment of tissue without the need for more invasive procedures. For example, catheters can be inserted into a body during ablation and mapping procedures performed on tissue within a body. Tissue ablation can be accomplished using a catheter to apply localized radiofrequency (RF) energy to a selected location within the body to create thermal tissue necrosis. Typically, the ablation catheter is inserted into a vessel in the body, sometimes with the aid of a pull wire or introducer, and threaded through the vessel until a distal tip of the ablation catheter reaches the desired location for the procedure involving a body tissue. The ablation catheters commonly used to perform these ablation procedures produce lesions and electrically isolate or render the tissue non-contractile at various points in the cardiac tissue by physical contact of the cardiac tissue with an electrode of the ablation catheter and application of energy, such as RF energy. By way of further example, another procedure, mapping, uses a catheter with sensing electrodes to monitor various forms of electrical activity in the body.
Known ablation catheter assemblies typically involve insertion of a catheter through a sheath or introducer where the standard catheter shaft size is 7 FR (French), the standard catheter tip size is 4-8 FR, and the standard sheath or introducer size is 8-11 FR. For purposes of this application, the term “FR (French)” means the French catheter scale used to measure the outer diameter of catheters. In the French gauge system as it is also known, the diameter in millimeters of the catheter can be determined by dividing the French size by three. Thus, an increasing French size corresponds with a larger diameter catheter. Typically, the outer diameter of the sheath or introducer is larger than the outer diameter of the catheter shaft and is also larger than the outer diameter of the catheter tip. A difficulty in obtaining an adequate ablation lesion using known ablation catheter assemblies for certain procedures is that conventional catheter assemblies have overall a large outer diameter that can potentially cause trauma. For instance, when performing transseptal catheterization or punctures across the septum of the heart, the fossa ovalis can be susceptible to trauma or injury. It is possible that, using known devices, two, three, or more transseptal punctures can have to be made through the same area of the fossa ovalis to get more of the catheter assembly from one side of the heart to the other side of the heart.
Another difficulty with known catheter assemblies such as those used for ablation procedures is that the ability to freely manipulate the catheter within the sheath or introducer is compromised or decreased because the catheter has greater overall contact with the interior walls of the sheath or introducer, as the standard catheter used for ablation normally has a constant diameter from the distal tip to the proximal handle end. Typically, the catheter and catheter tip is a single unitary assembly of constant diameter along the entire length of the catheter assembly, and typically, the sheath or introducer has a constant outer diameter and constant inner diameter along the entire length of the catheter assembly. When there is greater contact between the catheter and sheath or introducer, there is less degree of freedom of movement available in using the catheter assembly through transseptal punctures.
Another difficulty with known catheter assemblies such as those used for ablation procedures is that the catheter tips can not be of a large enough size to accommodate an electrically active element or to accommodate magnetic material to create a magnetic field, so that the magnetized catheter can be pulled and guided through the body and through the heart rather than pushed. Known catheter assemblies with magnetized elements often cannot accommodate a large enough magnetic material or element to create a magnetic field or they create unfavorable drag forces inside the catheter or sheath.
Known catheter assemblies such as those used for ablation procedures, include a standard electrical connector at their proximal end. These designs facilitate a connection between the catheter electrode wires and a multi-pin connector that is outside of a patient's body. Often the size of this connection is unimportant in most catheter assemblies; however, when the size of the connection is constrained, the electrical connector is more difficult to accommodate. This challenge is further exacerbated when the catheter assembly is irrigated, which adds the complicating element of a fluid lumen connection.
Accordingly, there remains a need for a catheter assembly that can be used for medical procedures such as ablation that addresses these issues and that will minimize and/or eliminate one or more of the above-identified deficiencies.